Answer:
Explanation:
Well, lets say you park your car on the top of a hill, gravitational energy prevents it from the car falling back. Or a snow pack, aka before a potential avalanche. Though gravity cannot keep it safe forever, gravitational energy keeps it from crashing asap. In this case, it gives you time to escape. Altogether, gravitational force keeps the earth in it's atmosphere.
Answer:
mass
Explanation:
Mass (M) is the measure of the amount of matter in an object. Mass is measured in grams (g). Mass is measured on a balance by comparing the object against other objects with known masses.
Answer:
Explanation:
a )
momentum of baseball before collision
mass x velocity
= .145 x 30.5
= 4.4225 kg m /s
momentum of brick after collision
= 5.75 x 1.1
= 6.325 kg m/s
Applying conservation of momentum
4.4225 + 0 = .145 x v + 6.325 , v is velocity of baseball after collision.
v = - 13.12 m / s
b )
kinetic energy of baseball before collision = 1/2 mv²
= .5 x .145 x 30.5²
= 67.44 J
Total kinetic energy before collision = 67.44 J
c )
kinetic energy of baseball after collision = 1/2 x .145 x 13.12²
= 12.48 J .
kinetic energy of brick after collision
= .5 x 5.75 x 1.1²
= 3.48 J
Total kinetic energy after collision
= 15.96 J
Answer:
No
Explanation:
The force of tension exerted by the string on the rock acts as centripetal force, so its direction is always towards the centre of the circle.
However, the direction of motion of the rock is always tangential to the circle: this means that the force is always perpendicular to the direction of motion of the rock.
As we know, the work done by a force on an object is
where
F is the magnitude of the force
d is the displacement of the object
is the angle between the force and the displacement
In this situation, F and d are perpendicular, so 
, therefore 
and the work done is zero:
